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From Eric Newton <eric.new...@gmail.com>
Subject Re: why the table not balance when i start a new tablet server
Date Mon, 22 Dec 2014 16:12:31 GMT
If you want to send me your logs in a private message, I can tell you
what's going on.

my question is that when i add a new tablet , why accumulo do not process
> balance ?


We have to be very careful with words.  Do you mean:

"add a new tablet" perhaps by splitting an existing table?
"add a new table"  which also creates a new tablet?
"add a new tablet server" which is what your display shows

Say you have 3 servers and 22 tables, and 3 of those tables have 2 tablets.

Accumulo will consider your current assignments as "balanced".

Why?

By default, each table has it's own balancer.  Since most of your tables
have one tablet, and the tablet is hosted, that table is balanced.

This somewhat surprising behaviour is seldom seen in practice.  Most users
do not have many tables with only a single tablet. Also, initial assignment
tends to spread tablets around, but balancing is conservative.  Observe
what happens when you do this:

> createtable test
> addsplits -t test 1 2 3 4 5 6 7 8 9

You should see 10 tablets of table "test" distributed evenly over your
three servers.

You can replace per-table balancing with a balancer that maintains a global
view of tablets:

In the shell:

> config -s
master.tablet.blalancer=org.apache.accumulo.server.master.balancer.DefaultLoadBalancer

You will have to restart the master for this change to take effect.

-Eric

On Sun, Dec 21, 2014 at 10:34 PM, 覃璐 <luq.java@gmail.com> wrote:

> thanks for replay.
>
> i check the debug log by grep balance,it show two type message:
> 1.[balancer.TableLoadBalancer] INFO : Loaded class
> org.apache.accumulo.server.master.balancer.DefaultLoadBalancer for table
> 2. [balancer.DefaultLoadBalancer] DEBUG: balance ended with 0 migrations
> there is no error or warn in the log and "Recent Logs" page.
>
> my question is that when i add a new tablet ,why accumulo do not process
> balance ?
> the new tablet server has no hosted table.
>
>
>  原始邮件
> *发件人:* Josh Elser<josh.elser@gmail.com>
> *收件人:* user<user@accumulo.apache.org>
> *发送时间:* 2014年12月21日(周日) 13:15
> *主题:* Re: why the table not balance when i start a new tablet server
>
> Like Eric said, check the master_*.debug.log (grep for 'balance' will
> probably show a reason why). Also, you should be able to see the same
> warning on the Accumulo monitor "Recent Logs" page.
>
> If you still can't find anything wrong looking at the logs, just restart
> the master process as a quick-fix.
>
> 覃璐 wrote:
> >
> >
> > i see the master debug log ,but i not found error log.
> >
> > why a tablet offine not balancing?? the tablet 02 dead yet,and i restart
> > it,but no table hosted in it.
> >
> >
> >
> > now i restart accumulo,i stop-all and start-all,why the tablet server
> > not balance,the 04 no table.
> >
> >
> >
> > 原始邮件
> > *发件人:* Eric Newton<eric.newton@gmail.com>
> > *收件人:* user@accumulo.apache.org<user@accumulo.apache.org>;
> > vines<vines@apache.org>
> > *发送时间:* 2014年12月20日(周六) 01:36
> > *主题:* Re: why the table not balance when i start a new tablet server
> >
> > If the master is not balancing, it will tell you why in the master debug
> > log.
> >
> > Some reasons for not balancing:
> >
> > 1) a tablet server is not responding to status requests
> > 2) a balance plan is already being executed
> > 3) a tablet is offline
> >
> > -Eric
> >
> > On Fri, Dec 19, 2014 at 9:43 AM, John Vines <vines@apache.org
> > <mailto:vines@apache.org>> wrote:
> >
> >     The default load balancer tries to balance each table, so if you
> >     have several small (single tablet) tables, they will never be
> >     migrated since they're currently balanced.
> >
> >
> >     On Fri, Dec 19, 2014 at 2:18 AM, 覃璐 <luq.java@gmail.com
> >     <mailto:luq.java@gmail.com>> wrote:
> >
> >
> >         i have three tablet server,but one had falt yet.
> >         then i re-start the tablet server,and i see it in the monitor
> >         page,but the table not balance,it only has a table which i
> >         create now.
> >         the document say that master will balance tables when tablet
> >         server falt,but why it not balance tables when a servlet server
> >         add??
> >
>
>

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